Explosively-actuated crimping tool



June 8, 1965 w. F. BROSKE ETAL EXPLOSIVELY-ACTUATED CRIMPING TOOL 2 Sheets-Sheet 1 Original Filed Jan. 12, 1959 INVENTOR. Mum/q f BEOSKE Bard/1am? E JFaYcOX June 1955 w. F. BROSKE ETAL 3,187,500

EXPLOSIVELY-ACTUATED CRIMPING' TOOL Original Filed Jan. 12, 1959 2 Sheets-Sheet 2 m I a :4 2

INVENTOR. ZJ/umM f fleas/(E BYd/uunn i. JFWCOX W, M r 4 United States Patent 7 Claims. (Cl. 60.26.1)

This application constitutes a division of our prior application, Serial No. 786,415, filed January 12, 1959.

In the art of making crimped electrical connections, it is desirable to generate high pressure by low weight, inexpensive tools capable of crimping large sized connectors (e.g., one-half million circular mils). Manually-operated tools capable of crimping large-sized connectors are heavy, bulky, expensive and require considerable stamina. Furthermore, they are not practical for use on connectors larger than 4/0. Even on connectors of the range No. 8 through 4/0, they are difiicult to operate and require a large amount of exertion to make a crimp.

Tools powered by electricity are bulky and expensive. Additionally, power is not always availableat the situs where the crimped connection is desired, e. g., a utility line.

Applicants provide a crimping tool operated by an explosive charge. A tool of this type permits development of a high thrust in a small, light, inexpensive assembly.

Explosive tools known to the prior art discharge the explosive gases into a barrel which is part of the assembly.

The discharge of these gases at firing temperature quickly results in erosion of the barrel. Applicants invention contemplates discharging these gases into a closed plastic chamber which is a part of a disposable cartridge. The gases quickly cool to a temperature range at which they are relatively harmless and are permitted to bleed gradually from the chamber. Furthermore, the plastic expands slightly during the firing cycle whereby it operates as a gas-tight seal. This also serves to reduce to a minimum the noise caused by the explosion.

Thus, it is an object of this invention to provide a means for crimping electrical connectors which is capable of crimping a large range of sizes up to extremely large connectors, quickly, easily, inexpensively, with a self-contained explosive device which is safe, noiseless and-emits very little noise.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a perspective view of a device in prefired condition, illustrating principles of this invention;

FIGURE 2 is a sectional view taken through plane 22 of FIGURE 1; 7

FIGURE 3 is a view similar to FIGURE 2 illustrating the device after firing;

FIGURE 4 is a partially cut-away perspective view of the cartridge shown in FIGURES 2 and 3; and

FIGURE 5 is a fragmentary view of the detonating head.

A tool, as shown in FIGURE 1, constituting a preferred 3,187,50h Patented June 8, 1965 embodiment of the invention, comprises a body member 10, with a detonating head 12 located thereon.

The particular body member illustrated in the drawings includes a C-shaped frame 14, with a fixed die 16 located within the frame. The fixed die has a die surface 18 capable of retaining a ferrule-type connector 20 with a conductor 22 inside of it. An opening 24 in the frame 14 contains a rod 26 slidably mounted therein and carries a die member 28 on one end so that it cooperates with the fixed die 16.

The detonating head 12 is aflixed to the body member coaxially of the opening 24. The head 12 is comprised of a cylindrical member 30 with a central aperture 32 adapted to retain a cartridge 34.

The cartridge (FIGURE 4) includes a plastic cylindrical tube 36 having a plug 38 fitted therein with an interference fit. One end of the tube is closed by a wall-like member 39. A primer 40 is located in the wall member 39 so that it is adapted to detonate a supply of explosive powder 41 contained in the cartridge 34 between the plug 38 and the wall member 39. The wall member 39 has a diameter slightly larger than the diameter of the cylinder -34 to form a rim 44 for seating the cartridge in the tool.

Polyethylene is highly satisfactory as a material for fashioning the cartridge and plug, although other plastics are suitable. The rim of the cartridge seats on a shoulder 46 at the outer end of the aperture 32. As shown in FIGURE 2, a cap 48 containing a spring-loaded firing pin aligned with the primer 40 is fitted over the cylindrical member 30. The cap 48 may be threaded or otherwise locked to the cartridge retaining portion of the detonating head, whereby it operates to lock the cartridge in firing position as well as providing means for detonating the powder charge 41.

A spring-loaded holding means, generally designated H (FIGURE 1), locates the conductor 22 with the connector 20 while the crimped connection is being made.

Operation the shoulder 46. It is noted that the rod 26 of the movable die is located centrally within the bore of the cartridge. The outside diameter of the rod 26 is slightly smaller than the inside diameter of the cartridge.

The detonating cap is locked in place so that the firing pin 59 is aligned with the primer cap 40. The firing pin 50 is then impacted against the primer cap 40 to detonate it. The primer cap, in turn, detonates the powder charge 41 to drive the plug 38 and the rod 26 toward the connector. The die 28 on the free end of the rod 26 is driven against the connector and conductor with sutficient thrust to crimp the connector and conductor into an intimate metallic mass forming a secure and etficient electrical connection.

The tool illustrated in the drawings is designed so that regulation of the size of the powder charge to the size of the connector controls the crimp depth or degree of compaction. Obviously, this could also be by the provision of regulated stops on the dies to control the die travel.

As shown in the drawings (FIGURE 2), the ram piston 26 is disposed so that one end of the ram abuts the plug 38. This relationship causes the crimping die 28 to penetrate deeply into the connector. A lesser penetration may be accomplished (e.g., for smaller connectors) by spacing the end of the ram from the plug. Since part of the energy is expended prior to the accomplishment of useful work, the total useful work performed is less, which results in a shallower crimp. The crimp depth may thus be varied according to spacing between the ram and the plug.

The phenomenon occurringwith the cartridge during the firing cycle is particularly interesting. The explosive gases generated by the burning of powder 41 cause the plastic cartridge to expand, thus forming a gas-tight seal with the opening 32 and cap 48. The plug 38 is driven toward the open end of the barrel 34. The combustion flame and hot gas are contained entirely Within the closed barrel 34 while the powder is burning. When the die 28 has compacted the connector and conductor to a degree whereby the resistance of the metal to further crimping is equal to the pressure in the barrel 34, the die travel ceases. The plastic plug 38, being softer than the metal a of the piston nod 26, is slightly extruded around the end of the rod. This extrusion pressure, in conjunction with a softening of the plastic plug 38 and softening of the plastic inner wall of the chamber 36 due to the heat generated by the hot gases and burning of the powder, causes fusion between the plug 38 and the cartridge wall 36 when theplug 38 is in its final position. This contains the hot gases Within the cartridge and prevents them from being expelled from the open end of the cartridge. Of course, the action is practically instantaneous so that the crimp is made Within microseconds after the detonation of the primer 40. Exploding the powder within the closed plastic chamber also serves to muflie the noise of the explosion so that, at most, only a slight report is heard.

After the charge is fired, the gases cool very quickly (again within microseconds) and the plastic tends to return to its original shape. The plastic in its expanded position is fitted very tightly about the primer cap to prevent the escape of combustion gases. Relaxation of the plastic causes the primer to fit loosely within the cartridge, thus permitting the combustion gases to escape. However, at the lower temperature, the gases are sufficiently cool so as to be innocuous and the combustion fiame is extinguished. The reduction in temperature results in a corresponding reduction in pressure so that the exhaust gases are bled out slowly under a very low pressure. In fact, if the gases were cooled sufliciently in the cartridge, a vacuum would form.

After the crimp is completed, the cap 48 is unlocked, the locator mechanism released, and the connector and conductor removed from the fixed die. The action of lifting the connector out of the tool causes the die 28 and the rod 26 to be pried upwardly. The rod 26 bears upon the plug 38 which is now fused to the cartridge. The resultant is that the entire cartridge is forced upwardly so that the rim 44 is raised from the surface 46. This permits the operator to get a grip on the spent cartridge to extract it from the tool quite easily.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

We claim:

1. The method of operating an explosive device which includes the steps of (1) detonating the explosive so that the combustion products are contained in a disposable cartridge, (2) permitting the explosion chamber to increase in volume so as to actuate a piston, and (3) sealing the chamber in its increased condition to prevent escape of combustion gases.

2. The method of claim .1 which includes the further step of slowly bleeding the combustion gases from the chamber after detonation is completed.

3. The method of actuating a movable member by an explosion comprising: (1) storing the explosive in a closed, removable package, (2) detonating the explosive within the package to perform useful work and retaining the combustion products within the package, and (3) removing the package from the device.

4. The method of actuating a movable member by an 7 explosion comprising the steps of: (1) storing the explosive in a closed plastic cartridge, removably disposed in the firing chamber, (2) detonating the explosive within the cartridge to perform useful work, (3) sealing the cartridge as a result of the detonation, to retain the combustion products within the chamber, and (4) removing the cartridge from the device with the combustion products therein.

5. The method of claim 4 wherein the sealing of the cartridge is effected by fusion of the plastic of the cartridge.

6. The method of actuating a movable member by an explosion comprising: (1) disposing the explosive within a cylinder that is closed at one end by a member integral with the cylinder and having a longitudinally movable closure member within the bore of the cylinder, so that the explosive is located between the movable closure member and the integral member, (2) placing the cylinder Within a firing chamber, (3) disposing a means for translating energy adjacent to the movable closure member, (4) detonating said explosive to drive the closure member longitudinally and thus cause the energy created to operate the means for translating energy, '(5) sealing the combustion products of the explosion within the cylinder and (6) removing the cylinder from the firing chamber.

7. The method of actuating a movable member by an explosion, comprising: (1) storing an explosive and detonator in an apertured container, (2) closing the aperture with a relatively movable means, (3) inserting the container in a chamber with the movable means adjacent a wall portion thereof, (4) detonating the explosive to actuate said movable means and member, (5) retaining the combustion products within the container upon removal of saidv container from said chamber.

References Cited. by the Examiner UNITED STATES PATENTS 3,007,409 11/61 Broske.

FOREIGN PATENTS 466,226 '6/50 Canada.

JULIUS E. WEST, Primary Examiner. EDGAR W. GEOGHEGAN, Examiner. 

3. THE METHOD OF ACTUATING A MOVABLE MEMBER BY AN EXPLOSION COMPRISING: (1) STORING THE EXPLOSIVE IN A CLOSED, REMOVABLE PACKAGES, (2) DETONATING THE EXPLOSIVE WITHIN THE PACKAGE TO PERFORM USEFUL WORK AND RETAINING THE COMBUSTION PRODUCTS WITHIN THE PACKAGE, AND (3) REMOVING THE PACKAGE FROM THE DEVICE. 